1. Field of Invention
This invention pertains to a rear suspension assembly for a drag racing vehicle. More particularly, this invention pertains to rear suspension assembly that includes members that stabilize the rear axle of a vehicle.
2. Description of the Related Art
Drag racing vehicles have unique requirements compared to oval or round track race vehicles or street vehicles. Not only must a drag racing vehicle have sufficient horsepower to win races, but that horsepower must be efficiently transferred into forward motion through the rear tires. Many factors contribute to the dynamic response of a drag racing vehicle during a run. The tuning of the rear suspension is crucial during the start because it is desirable for the majority of the vehicle weight to be supported by the rear tires equally to ensure straight launches and maximum traction.
Drag racers typically use two types of non-independent rear suspensions to improve the performance of their vehicles. A ladder bar suspension has one connection point forward and two connection points at the rear axle for each of two ladders. The ladder bar suspension allows the rear end to move in an arc having a center at the forward connection point. A four-link suspension has four links, two on each side of the rear differential, connecting the rear axle to the vehicle. The four-link suspension allows the rear end to move in an arc with a center well away from the forward connection points at a point called the instant center.
With both the ladder bar and the four-link suspensions, it is known to use a diagonal crosslink to prevent racking of the suspension. Racking is the sideways movement of the rear end relative to the centerline of the vehicle. The diagonal crosslink has one end attached to one front connection point and the other end attached to the rear axle housing diagonally opposite the front connection point. The ladders and four-links are arranged in a front-to-back configuration substantially parallel to the longitudinal axis of the vehicle and the crosslink is at an angle to the longitudinal axis, when viewed from above. The diagonal crosslink does not prevent roll or twisting of the rear axle.
It is also known to use an anti-roll bar with these suspensions in order to increase the suspension's roll stiffness, which is its resistance to roll in turns. Anti-roll bars are also called sway bars, anti-sway bars, and roll bars. Anti-roll bars are typically attached to the vehicle and the rear axle housing independent of the ladder bars and four-link suspension components. Drag racing vehicles have little need for anti-roll bars because these vehicles typically travel in a straight line. But, drag racing vehicles have a need for rear suspensions that equalize the loading of each rear tire as power is applied to the tires from the drive chain.